This study is a continuation of a program evaluating uses of the EEG in clinical psychopharmacology. Since 1964, we have developed programs for quantifying changes in EEG frequency, amplitude, and variability using digital computer methods of period analysis and power- spectral-density analysis. We use these methods to define EEG profiles of drugs in normal male volunteers and in psychiatric patients. We interpret the EEG profiles of numbered compounds to define their clinical applications; to relate the EEG changes to the behavioral effects of drugs; to predict individual therapy; and to measure bioavailability and CNS equivalence of different drug formulations.